Hello 
I just thought i would stop by and share a couple of my node groups that i’ve made.
They come in handy in a lot of my projects, so hopefully they can be of use to some of you too.
The car paint node group is not a shader, it outputs Base Colour, Speckle Colours, Roughness and also has a mask output too, to aid in quick creation of car paint shaders.
It is able to adjust the weight, scale and distribution of two seperate sets of speckles. Along with an adjustable roughness output for the base and speckles.
No U.Vs required, works well with the position vector input from the geometry node.
I also added in my metallic Shader Nodegroup in the file too, as i think its a nice timesaver and wanted to share it (It’s based on the Realistic PBR materials tutorials on the blender guru website) It also shows of the CarPaint Node functions pretty well too.
If anyone finds anyway to improve either the look or optimization of any of these nodegroups then please let me know, and feel free to make any adjustments, integrations or changes as you wish.
Here is the .blend file - CarPaint.blend (3.46 MB)
And here is a screenshot of the interface for the nodegroups.
(The HueModWeight feature basically just increases the influence of SpeckleColour2)
And if you want to append the nodegroups to another scene, The Carpaint is called “CarPaint(Col,Rough,Mask)” And the Metallic shader is called “MetallicBSDF”.
